Tasmanian Native Hen, Tribonyx mortierii

Tasmanian Native Hen and chicks
(Photograph by Steve Johnson)

The Tasmanian Native Hen is a distant relative of the domestic hen. It is found only in Tasmania, being distributed throughout the State except for the west and southwest. It ranges from the coast to areas 1000 m above sea level. Like the thylacine and Tasmanian devil, native hens became extinct on the mainland around the time the dingo arrived in Australia.

Tasmanian Native Hens are most common on marshes, river flats and near fresh water streams and rivers. Their ideal habitat is short, grazed pasture and damp pasture near streams with grassy vegetation for nesting. Although they cannot fly, they are good swimmers and very fast runners. When a Native Hen senses danger they often flick their tail to warn others and if chased will seek the shelter of grass or reeds. Using their short wings for balance, they are capable of running at 50 km per hour.

Description

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A Native Hen stands about 45 cm tall, has a pale yellow bill and a bright red eye. They are coloured green-brown above and slate-grey on the flanks with white flashes. The tail and abdomen are black. There are two other birds that may be confused with the Tasmanian Native Hen as they are similar in body-shape and size. The Dusky Moorhen, which is rare in Tasmania, can be distinguished by its sooty coloured plumage, brown eye, white lines on its tail and red bill with a yellow tip. The more common Purple Swamphen is identified by its bright red bill, deep blue belly and white tail.

Native Hens are very social and make a number of calls including a loud, distinctive rasping 'see-saw'. This call is often carried out in unison, with several birds joining in to produce a cacophony of noise.

Although Native Hens prefer open country around lagoons, water courses and pastures, they may visit urban gardens. They usually feed at dawn and dusk on grasses and seeds. Insects are eaten by young Native Hens. Unfortunately, the fondness that Native Hens have for clover and legumes may bring them into conflict with some farmers. See our pages on Living With Wildlife.

Breeding

They breed from July to December and typically lay around 5 eggs although 9 - 10 is not uncommon. They are also capable of producing more than one clutch per year. The social structure of Native Hens is unique. Research has shown that within a population of native hens, roughly half are monogamous (have only one mate) and half polygamous (have more than one mate). Polygamy in Native Hens most often occurs in groups of 3 - 5 individuals of which only one is female. This female actually mates with all other males in the group, a behaviour called polyandry. In addition, juvenile Native Hens assist with the raising and protection of their brothers and sisters.

Population regulation

Native Hen populations are largely controlled by predation and food availability. In years when food is plentiful, hens will lay up to 10 eggs and raise 2 broods, but when food is scarce they will lay fewer eggs and only raise a single brood. Native Hens are preyed upon by quolls and Tasmanian Devils, and a large range of birds from kookaburras and ravens to gulls and birds of prey. Eggs are taken by quolls, Tasmanian Devils, ravens and marsh harriers. Even adult Native Hens fall prey to devils and eagles. The high level of predation that Native Hens suffer is, to a degree, counteracted by the large number of young they have.

When, where and how to see Native Hens

Native Hens can be seen on most riverside farmland throughout the state. The Derwent, Tamar, North Esk and South Esk rivers are great places to start. Sightings are guaranteed on Maria Island where a large introduced population has been established. They'll meet you at the ferry!

Distribution

Found in suitable habitat throughout mainland Tasmania except the far south west.